1. Field of the Invention
The invention relates to a method for the trickle resin impregnation of parts containing electrical lines and an apparatus for implementing this method.
2. Discussion of Related Art
It is well known that electrical lines, electrical elements, etc. may be coated with a layer of resin or embedded completely in a protective resin composition for attaining supplementary insulation. For electrical lines which are subjected to dynamic stresses, such as windings of electric motors, that is, armature windings, stator windings, etc., supplementary mutual insulation can not only be provided by means of a so-called trickle resin impregnation with an external layer of resin, but may also be impregnated completely by the resin layer. This is done to obtain an effective protection, a particularly good stabilization of the windings and lines with respect to one another and, of course, to obtain the insulation previously mentioned.
Problems with such trickle resin impregnation methods arise because the resin composition, which is to be applied to the winding, such as an armature winding, should be sufficiently fluid so as to penetrate, as far as possible, into all the interstices and openings and to completely surround the lines. The resin should be kept sufficiently viscous, so that, during the impregnation, the resin will not drip off the windings. Above all, it is also necessary to ensure that after the resin impregnation is applied, the solidification of the applied composition preferably sets in immediately. For this purpose, a curing agent must be added in the appropriate dosage to the impregnating resin and, above all, mixed in well with it.
At least in the case of the impregnation of certain parts of electrical components, such an impregnating method can only be carried out intermittently. For example, in the trickle resin impregnation of the armature of an electric motor, when the treatment of the armature is finished, the armature must be carried away first, which is to be treated, is brought along. At this time, the impregnating stream of the resin is interrupted and other interruptions can not be excluded. Such interruptions, however, can cause the curing agent-containing resin to cure partially in the region of the outlet nozzle and, under some circumstances, to block the nozzle increasingly. In such an event, it is no longer possible to make do with the intermittent timing. On the other hand, if the amounts of curing agent are too small, adequately rapid stabilization of the liquid resin cannot be attained, which can create other problems.
In any case, the apportioning of the curing agent, which is to be added to the resin composition, is critical. For example, only one part of the curing agent for 99 parts of synthetic resin is to be used as a possible, usual formulation.
It is desirable to provide for the trickle resin impregnation of the armature winding of an electric motor, but the present invention is not limited to this special application. Instead, the invention comprises other possible applications no matter what part is to be impregnated. The synthetic resin, which is to be applied, flows through a free path which runs, for example, from the outlet of a nozzle to the point at which it strikes the object that is to be impregnated.